U.S. patent application number 13/200669 was filed with the patent office on 2012-04-05 for transport arrangement for printing materials in a printing machine.
Invention is credited to Dimitrios Kostudis.
Application Number | 20120082501 13/200669 |
Document ID | / |
Family ID | 45889961 |
Filed Date | 2012-04-05 |
United States Patent
Application |
20120082501 |
Kind Code |
A1 |
Kostudis; Dimitrios |
April 5, 2012 |
Transport arrangement for printing materials in a printing
machine
Abstract
In a transport arrangement for printing materials in a printing
machine, said transport arrangement comprising one rotatably
supported first transport roller with a first shaft and a roller
body having a first outside diameter and comprising at least one
rotatably supported second transport roller with a second shaft and
a roller body having a second outside diameter, said second
transport roller when viewed in transport direction of the printing
material arranged downstream of the first transport roller, a
actuating arrangement is provided for the adjustment of the outside
diameter of the first or the second transport rollers or both. The
actuating arrangement allows the adjustment of the outside diameter
in such a manner that the outside diameters of the first or of the
second transport rollers or both are at a fixed ratio relative to
each other.
Inventors: |
Kostudis; Dimitrios; (Wedel,
DE) |
Family ID: |
45889961 |
Appl. No.: |
13/200669 |
Filed: |
September 28, 2011 |
Current U.S.
Class: |
400/611 |
Current CPC
Class: |
B65H 2511/14 20130101;
B65H 2511/14 20130101; B65H 18/103 20130101; B65G 13/04 20130101;
B65H 2801/21 20130101; B65H 2513/11 20130101; B65H 2403/921
20130101; B65H 2557/61 20130101; B65H 2404/11211 20130101; B65H
2513/11 20130101; B65H 2220/01 20130101; B65H 2220/04 20130101;
B65H 2406/15 20130101 |
Class at
Publication: |
400/611 |
International
Class: |
B41J 11/04 20060101
B41J011/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 29, 2010 |
DE |
102010046962.9 |
Claims
1. A transport arrangement for printing materials in a printing
machine, said transport arrangement comprising: one rotatably
supported first transport roller with a first shaft and a roller
body having a first outside diameter; at least one rotatably
supported second transport roller with a second shaft and a roller
body having a second outside diameter, said second transport roller
is arranged downstream of the first transport roller and an
actuating arrangement for the adjustment of the outside diameter of
at least one of the first or the second transport rollers in such a
manner that the outside diameters of the first or of the second
transport rollers or both are at a fixed ratio relative to each
other.
2. The transport arrangement as in claim 1, wherein the fixed ratio
is equal to 1.
3. The transport arrangement as in claim 1 wherein the ratio is
fixed before the printing machine is operated.
4. The transport arrangement as in claim 1 wherein the actuating
arrangement is actuated while at least one of the transport rollers
is rotating.
5. The transport arrangement as in claim 1, wherein the transport
rollers are driven by a common driving motor.
6. The transport arrangement as in claim 1, wherein the actuating
arrangement are pneumatically, hydraulically, mechanically and/or
piezoelectrically driven.
7. A printing machine comprising at least one printing unit and at
least one transport arrangement.
8. A method for calibrating a transport arrangement for printing
materials in a printing machine comprising one first transport
roller having a first outside diameter and at least one second
transport roller having a second outside diameter, said method
comprising the step of adjusting the outside diameter of at least
one of the second transport rollers to a dimension that is at a
fixed ratio relative to the outside diameter of the first transport
roller.
9. The method of claim 8, wherein the fixed ratio is equal to
1.
10. The method of claim 8 wherein the ratio is fixed before the
printing machine is operated.
11. The method of claim 8 wherein the ratio is fixed while at least
one transport roller is rotating.
12. The method as in claim 8 wherein the outside diameter is
adjusted pneumatically, hydraulically, mechanically or
piezoelectrically or in a combination of two or more of these.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a transport arrangement for
printing materials in a printing machine as well as to a method for
calibrating such a transport arrangement.
BACKGROUND OF THE INVENTION
[0002] In printing machines or similar machines for processing
printing materials, a printing material is transported from a
supply roll or a stack of sheets in a feeder unit through a
printing or processing section to a delivery unit where the
completely processed printing materials are deposited. While the
printing material is processed in the printing machine, said
material mostly moves over a plurality of transport rollers or
transport belts or both which are successively arranged in
transport direction. During that movement, the sheet or the web of
printing material is mostly in engagement with several transport
rollers. Therefore, the transport rollers should move as
synchronously as possible because, otherwise, the printing material
can be damaged, an imprecise printed image or other positioning
errors or both can occur. For example, in multi-color printing,
there is the problem that not all the colors are precisely
superimposed (registration error). In the same way, it can happen
that the printing material does not move precisely into a cutting
device.
[0003] Consequently, the successively arranged transport rollers in
such a printing machine should transport all the printing materials
at the same speed when a printing material web is transported or
when sheets are transported at equal relative distances.
Alternatively, the individual transport rollers have to maintain an
exact ratio of speeds relative to each other if they have different
speeds that are adapted to each other, for example, in order to
convey sheets at increasing or decreasing distances from each
other.
[0004] For example, it is possible to achieve such an identical
transport speed or such an identical ratio of transport speeds of
the successively arranged transport rollers in that several
transport rollers are driven by the same driving motor. Here, the
transport rollers are connected, for example, by arrangement of
toothed gears or a driving belt and have exactly the same outside
diameters. The transport rollers for such a transport arrangement
comprising a common drive therefore have to maintain highly exact
tolerances, so that said transport rollers have exactly the same
outside diameters and thus drive a printing material at the same
transport speed with the same input rate of revolutions.
[0005] If, alternatively, transport rollers are used having been
made with less narrow tolerances and thus displaying minimally
different outside diameters, the input rate of revolutions has to
be calibrated or controlled within narrow limits, so that the
transport speed of a conveyed printing material will be the same
for each transport roller, even if the outside diameters of the
rollers are minimally different.
[0006] Narrow tolerances also apply to transport arrangements
comprising successively arranged transport rollers having different
transport speeds. This is to say that the different driving speeds
be precisely maintained. In the same way, it would be possible to
achieve exactly the same driving speed ratios in that the outside
diameters of the transport rollers that are used are made at a
fixed ratio. Alternatively, the input rates of revolution of the
transport rollers would have to be kept at an exactly determined
ratio.
[0007] The object of the present invention is to permit greater
tolerances making transport rollers, to implement cost savings as a
result of this and, optionally, to increase the flexibility of the
transport process.
SUMMARY OF THE INVENTION
[0008] In a transport arrangement for printing materials in a
printing machine, said transport arrangement comprising one
rotatably supported first transport roller with a first shaft and a
roller body having a first outside diameter and comprising at least
one rotatably supported second transport roller with a second shaft
and a roller body having a second outside diameter, said second
transport roller when viewed in transport direction of the printing
material arranged downstream of the first transport roller, a
actuating arrangement is provided for the adjustment of the outside
diameter of the first or the second transport rollers or both. The
actuating arrangement allows the adjustment of the outside diameter
in such a manner that the outside diameters of the first or of the
second transport rollers or both are at a fixed ratio relative to
each other.
[0009] The object of the present invention is achieved with a
transport arrangement for printing materials in a printing machine.
In particular, the transport arrangement includes one rotatably
supported first transport roller with a first shaft and a roller
body having a first outside diameter at least one rotatably
supported second transport roller with a second shaft and a roller
body having a second diameter is arranged when viewed in transport
direction of the printing material downstream of the first
transport roller. Actuating arrangements for the adjustment of the
outside diameter of the first or the second transport rollers or
both are provided in such a manner that the outside diameters of
the first or the second transport rollers or both are at a fixed
ratio relative to each other. As a result of this, it is possible
to compensate for variations of the transport speeds between
different transport rollers, at which speeds the transport rollers
transport the printing material. It is also possible to adjust
desired speed differences for process-specific or other reasons
(for example, temperature, humidity) in a controlled manner.
[0010] In one embodiment the fixed ratio is equal to 1. Thus, a
plurality of transport rollers, said rollers successively arranged
in transport direction of the printing material, can provide the
same transport speed with the same input rate of revolutions and
with deviating dimensions.
[0011] In one embodiment of the transport arrangement, the ratio is
determined before the printing machine is operated. As a result of
this, a simple calibration of the printing machine is
performed.
[0012] In another embodiment the transport arrangement is actuated
while at least one of the transport rollers is rotating. This
results in a dynamic adjustability.
[0013] In a transport arrangement, wherein the transport rollers
are driven by a common driving motor, this is beneficial as
components and hence costs are saved and as the control of the
drive is facilitated.
[0014] Depending on the embodiment of the transport arrangement,
the actuating arrangement are pneumatically, hydraulically,
mechanically or piezoelectrically driven or both. The pneumatic,
hydraulic and piezoelectric driving modes are suitable for dynamic
adjustments; the mechanical driving mode is cost-favorable.
[0015] Furthermore, the object of the present invention is achieved
by a printing. The printing machine includes at least one printing
unit and at least one transport arrangement.
[0016] In addition, the object of the present invention is achieved
by a method for calibrating a transport arrangement for printing
materials in a printing machine. The printing machine includes one
first transport roller having a first outside diameter and at least
one second transport roller having a second outside diameter. The
method includes the step of adjusting the outside diameter of at
least one of the second transport rollers to a dimension that is at
a fixed ratio relative to the outside diameter of the first
transport roller.
[0017] In one embodiment of the method, the fixed ratio is equal to
1. Thus, a plurality of transport rollers arranged successively in
transport direction of the printing material can provide the same
transport speed with the same input rate of revolutions and with
different dimensions.
[0018] In one embodiment of the method, the ratio is fixed before
the printing machine is operated. As a result of this, it is
possible to perform a simple calibration of the printing
machine.
[0019] In another embodiment of the method, the ratio is fixed
while at least one transport roller is rotating. This results in a
dynamic adjustability.
[0020] Depending on the embodiment of the transport arrangement,
the outside diameter is adjusted pneumatically, hydraulically,
mechanically or piezoelectrically or in combination of two or more
of these. The pneumatic, hydraulic and piezoelectric driving modes
are suitable for dynamic adjustments; however, they are expensive
and complex. The mechanical driving mode is cost-favorable;
however, it is rather more suitable for the calibration of the
transport rollers before the printing machine is operated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows a schematic side view of a printing machine,
said printing machine comprising one embodiment of a transport
arrangement for printing materials.
[0022] FIG. 2 shows a schematic side view of another embodiment of
a transport arrangement for printing materials, said transport
arrangement is usable in the printing machine.
[0023] FIG. 3 shows a schematic of an exemplary embodiment of a
transport roller that is used in the transport arrangement.
[0024] FIG. 4 shows a schematic of an alternative exemplary
embodiment of a transport roller that is used in the transport
arrangement.
[0025] FIG. 5 shows a schematic of another alternative exemplary
embodiment of a transport roller that is used in the transport
arrangement of FIG. 1 or 2; and
[0026] FIG. 6 shows a schematic, partially in section, of another
exemplary embodiment of a transport roller that is used in the
transport arrangement of FIG. 1 or 2.
DETAILED DESCRIPTION OF THE INVENTION
[0027] The invention, as well as additional details and advantages
of said invention, will be explained hereinafter with the use of
preferred exemplary embodiments and with reference to the
figures.
[0028] It should be noted that the terms top, bottom, right and
left, as well as similar expressions, used in the description
hereinafter relate to the orientations or arrangements depicted in
the figures and are only used to describe the exemplary
embodiments. However, these expressions are not to be understood to
have a restrictive meaning.
[0029] FIG. 1 is a schematic side view of a printing machine 1,
this is an example of a processing machine. The printing machine 1
includes a feeder unit 2 with a first printing material roll 3 and
a delivery unit 4 with a second printing material roll 5. A
printing material web 7 moves along a transport path from the first
printing material roll 3 to the second printing material roll 5.
Between the feeder unit 2 and the delivery unit 4 and along the
transport path of the printing material web 7, there is a printing
section 8 wherein several printing stations 9 for different colors
are arranged. The printing material web 7 is also guided in the
printing machine 1 over at least one transport roller 12.
Furthermore, the printing machine 1 includes a driving unit 13 with
a driving roller 14, said driving roller are intended for conveying
the printing material web 7 from the first printing material roll 3
in the direction to the second printing material roll 5.
[0030] The driving unit 13 includes a driving disk 14, a driving
motor 15 as well as a driving belt 16. The driving belt 16 extends
around the driving disk 14 and is in a driving relationship with
the transport roller disks 17 on the transport rollers 12. The
driving unit 13 is connected to a frame 18 of the printing machine
1.
[0031] During operation, the driving motor 15 is supplied with
power and rotates the driving disk 14. The driving disk 14 drives
the transport roller disks 17 via the driving belt 16 and, thus,
also drives the plurality of the transport rollers 12 (here five
transport rollers 12a, 12b, 12c, 12d, 12e). Hereinafter, the
transport rollers will generally be identified by reference number
12, wherein an added letter identifies any specific transport
roller, respectively.
[0032] FIG. 2 shows an embodiment of a transport arrangement 20 for
printing materials, said transport arrangement comprising two
transport rollers 12a, 12b and one main drive 13. The main drive 13
and the transport rollers 12a and 12b are mounted to a frame 18 of
a printing machine 1. The transport rollers 12a and 12b are
arranged so as to transport a printing material web 7. In order to
ensure a uniform transport of the printing material web 7 the
transport speed Va imparted by the left transport roller 12a should
be equal to the transport speed Vb imparted by the transport roller
12b. The transport speed V of a transport roller 12 is a function
of its outside diameter and its input rate of revolutions. The
input rate of revolutions of a transport roller 12 is determined by
the rate of revolutions of the main driving motor 15 as well as by
the diameter of the main driving disk 14 and the transport roller
disk 17 of the respective transport rollers 12.
[0033] Relative differences of the transport speeds Va, Vb of the
two transport rollers 12a, 12b can occur, in particular, due to
differences in the dimensions of the main driving disk 14, the
transport roller disks 17a, 17b, and the transport rollers 12a,
12b. Fluctuations of the rate of the input rate of revolutions of
the main driving motor 15, of course, are in most cases not
desirable; however, they do not have the effect that an existing
(and sometimes even desired) difference of the transport speeds Va,
Vb will be changed. This is because changes of the input rate of
revolutions of the main driving motor 15 lead to uniform changes of
the transport speed Va as well as of the transport speed Vb.
[0034] In one case, the operator of the printing machine 1 can
request for the transport speeds Va and Vb to be exactly the same.
In another case, the operator of the printing machine can request
for the transport speeds Va and Vb to be at a fixed ratio with
respect to each other. For example, the transport speed Vb is by
20% greater than the transport speed Va. This might be the case
when, instead of a continuous printing material web 7, a printing
material is transported that is fed in form of sheets by the feeder
unit 2 of the printing machine 1. It is, thus, possible to
accelerate a sheet that is located above the second transport
roller 12b and is conveyed at the greater transport speed Vb. In
this manner, a greater distance between successive sheets is
achieved.
[0035] At least one of the transport rollers 12 has an actuating
arrangement 19 for adjusting the outside diameter of this transport
roller 12. FIGS. 3, 4, 5 and 6 show different embodiments of a
transport roller 12 as well as an associated actuating arrangement
19 for adjusting its outside diameter. Hereinafter, FIGS. 3 through
6 show different embodiments of transport rollers 12 and an
actuating arrangement 19 that will now be described. To the extent
that this is possible, the same reference signs are used for
different embodiments, provided these are similar regarding design
and function. The reference signs used in FIG. 3 will be
characterized by special character (') in FIG. 4, by special
character ('') in FIG. 5, and by special character (''') in FIG.
6.
[0036] FIG. 3 shows an exemplary embodiment of a transport roller
12 comprising a roller body 20 and a shaft 21, said roller body 20
is mounted on said shaft 21. The shaft 21 extends transversely to
the transport direction of the printing material web 7 and is
supported so as to be rotatable relative to the frame 18 of the
printing machine 1. Also, the transport roller disk 17 is attached
to the shaft 21, however, transport roller disk 12 is not shown in
the view of FIG. 3.
[0037] The roller body 20 is cylindrical and consists of an elastic
material, for example, of rubber or of a foam material. The roller
body 20 has a bore 22 that is indicated in dashed lines in FIG. 3,
said bore 22 extending along the rotational axis of the roller body
20. The shaft 21 extends through the bore 22 and has a thread 23 in
the region of the bore 22. To the right and to the left of the
roller body 20, a disk 24 each is arranged. The disks 24 also have
a not specifically shown central bore through which extends the
shaft 21, said shaft is fitted in a manner so as to have play. To
the right and to the left of the disks 24 are the nuts 25, these
representing the fitting arrangement 19 that are screwed on the
thread 23 of the shaft 21. Alternatively, it is also possible to
provide a nut 25 on only one side of the roller body 20, in which
case the shaft 21 is provided with a shoulder on the opposite
side.
[0038] Depending on the distance of the nuts 25 and the adjacent
disks 24, a more or less strong axial force is exerted on the
roller body 20. If the distance of the nuts 25 and the cams 24
corresponds to the length of the roller body 20, said roller body
is not compressed and no axial force is applied to the roller body
20. The outside diameter of the roller body 20 in relaxed state
corresponds to the diameter d shown in FIG. 3.
[0039] As soon as one of the nuts 25 is screwed toward the other
nut 25, the disks 24 are moved toward each other, and the
interposed roller body 20 is subjected to an axial force. This
application of an axial force causes the roller body to be
compressed lengthwise, as a result of which the compressed material
of the roller body bulges outward. The roller body 20 becomes
barrel-shaped and assumes a larger outside diameter D. The closer
the nuts 25 are screwed toward each other, the smaller is the axial
length of the roller body 20 and the larger becomes the curvature
of the roller body 20 and thus the outside diameter of said roller
body.
[0040] FIG. 4 shows another exemplary embodiment of a transport
roller 12', said roller having a similar design as the transport
roller 12 of FIG. 3. Therefore, the description will be slightly
abbreviated. The transport roller 12' has a roller body 20' and a
shaft 21'. A bore 22' extends through the roller body 20'. The
shaft 21' of the transport roller 12' has a thread 23' which is in
engagement with two nuts 25', the latter is the actuating
arrangement 19'. Several disks 24' are arranged between the nuts
25'. The roller body 20' of the transport roller 12' is divided
into three parts, with a disk 24' arranged between each of the
three parts and also to the right and to the left of said three
parts.
[0041] As described above regarding the transport roller 12 of FIG.
3, the outside diameter of the three-part roller body 20 changes as
a function of the distance of the nuts 25'. The smaller the
distance of the nuts 25' is, the more the three-part roller body
20' is compressed. As a result, the three parts of the roller body
20' take on a barrel form as is obvious from FIG. 1 and as is
indicated in FIG. 3. The outside diameter of the roller body 20'
varies between a diameter d in relaxed state and a diameter D in
screwed-together state.
[0042] FIG. 5 shows another exemplary embodiment of a transport
roller 12''. The transport roller 12'' has a roller body 20'' as
well as a shaft 21''. A bore 22'' extends through the roller body
20''. A thread 23'' is provided on the shaft 21''. The thread 23''
may be a single thread, or may consist of two threaded regions. The
two threaded regions may have the same or different thread
orientations, i.e., they may be right-hand or left-hand threads or
both. Also, in the embodiment of the transport roller 12'' of FIG.
5, there is a disk 24'' each provided to the right and to the left
of the roller body 20''. In the embodiment of FIG. 5, the disks
24'' do not have a passage hole but they have an internal thread on
their inside bore 22''. The internal thread of the disk 24'' is in
engagement with the external thread 23'' of the shaft 21'', and
these threads together form the actuating arrangement 19''. In this
manner, the nuts 25, 25' of the previously described embodiments is
omitted. By screwing the disks 24'' toward each other and away from
each other the roller body 20'' of the transport roller 12'' is
compressed more or less in axial direction. As in the
aforementioned exemplary embodiments, the roller body 20'' adopts a
barrel form as the disks 24'' are screwed closer toward each other.
The outside diameter of the roller body 20'' thus becomes larger or
smaller as a function of the distance of the disks 24''.
[0043] FIG. 6 shows another exemplary embodiment of a transport
roller 12'''. The transport roller 12''' has a roller body 20''' as
well as a shaft 21'''. Disks 24''' are arranged to the right and to
the left of the roller body 20'''. The disks 24''' are rigidly
connected with the shaft 21'''. The shaft 21''' has an axially
extending longitudinal bore 26''', a sectional view of which is
seen on the right side of FIG. 6. The longitudinal bore 26'''
extends from the right end of the shaft 21''' up to the region of
the roller body 20'''. In the region of the roller body 20''', the
shaft 21''' has a transverse bore 27''' that opens toward an
interior space formed by the roller body 20'''. The longitudinal
bore 26''' extends at least up to the transverse bore 27''', so
that a flow agent communication is established between these
bores.
[0044] In the exemplary embodiment of FIG. 6, the roller body 30'''
is cylindrical and has an outside diameter that approximately
corresponds to the outside diameter of the disks 24'''. The roller
body 20''' is approximately U-shaped in cross-section and consists
of an elastic material such as, for example, rubber. The roller
body 20''' is impermeable to the flow agent and is connected with
the disks 24''' so as to be tight with respect to the flow
agent.
[0045] The transport roller 12''' of FIG. 6 can also be adjusted
regarding its outside diameter in that the outside diameter of the
roller body 20''' is changed. The longitudinal bore 26'''
communicates with a (not illustrated) source of a pressurized flow
agent, for example, a pressurized air source or a hydraulic
pressure source. Depending on the supply pressure of the flow agent
source, the pressurized flow agent is guided through the
longitudinal bore 26''' and the transverse bore 27''' into the
inside of the roller body 20'''. The flow agent distributes itself
on the inside of the roller body 20''' and exerts a radially
outward-directed force on the roller body 20'''. As a result of
this, the outside diameter of the roller body 20''' is changed.
Thus, the source of pressurized flow agent, the longitudinal bore
26''' and the transverse bore 27''' form the actuating arrangement
19''' in the exemplary embodiment of FIG. 6. The outside diameter
of the roller body 20''' can vary between a small diameter d in
relaxed state without the application of a pressurized flow agent
and a large diameter D in a state with the application of
pressure.
[0046] In the transport arrangements of FIGS. 1 and 2, it is
possible to use one or more transport rollers 12, 12', 12'' or
12'''. As will be obvious to the person skilled in the art, it is
possible to adjust a different outside diameter of the transport
rollers 12, 12', 12'', 12''', depending of the design of the
transport rollers 12, 12', 12'', 12'''. With the same input rate of
revolutions, it is possible to vary the transport speed Va or Vb
provided by the transport roller 12.
[0047] For example, supposing a case in which the transport speed
Vb of the right transport roller 12b is smaller by 5% than the
transport speed Va of the left transport roller 12a. This
difference results from the fact that the outside diameters of the
transport rollers 12a and 12b, as well as the outside diameters of
the transport roller disks 17a, 17b of the left and right transport
rollers 12a and 12b are different due to manufacturing
tolerances.
[0048] At least one of the transport rollers 12a, 12b of the
transport arrangement of FIG. 2 is adjustable with respect to its
outside diameter and has a design as shown in FIGS. 3 through 6.
Regarding the aforementioned example, it is assumed that at least
the transport roller 12b has a design as in FIGS. 3 through 6.
[0049] For calibrating the transport arrangement of FIG. 2, the
outside diameter of the transport roller 12b is enlarged by way of
the respective actuating arrangement 19 until the difference of 5%
of the two transport speeds Va and Vb has been equalized for. To
accomplish this, the distance of the disks 24, 24', 24'' is varied
(FIGS. 3, 4 and 5) by screw action, or the outside diameter of the
roller body 20''' is enlarged by injection of a pressurized flow
agent (FIG. 6).
[0050] The ratio of the transport speeds Va and Vb is adjusted by
changing the outside diameter of the roller body 20, 20', 20'',
20''' not only to a ratio of 1 (equalization of the difference of
5%). The outside diameter of the transport roller 12 is enlarged
further, so that the transport speed Vb is, for example, 1.2 times
the transport speed Va.
[0051] The transport arrangement for printing materials is adjusted
or calibrated or both before the printing machine 1 is operated,
for example in a factory before delivery of the printing machine.
In such cases, the adjustment of the transport rollers 12 is
suitably accomplished with the simply designed exemplary
embodiments of the transport rollers 12 of FIGS. 3, 4 and 5 because
said transport rollers is made in a cost-effective manner.
Alternatively, it is possible to perform a dynamic adjustment of
the outside diameters of the transport rollers 12 during the
operation of the printing machine. For this, the embodiment of FIG.
6 would be suitable, for example
[0052] So far the description has been of a pneumatic, hydraulic or
mechanical adjustment of the outside diameter or of a combination
of two or more of these. A piezoelectric drive represents another
suitable driving mode for the dynamic adjustment of the outside
diameter of the transport rollers 12. A piezoelectric driving
element is interposed, for example, between one of the nuts 25, 25'
or a shoulder of the shaft 21, 21', 21'', and the roller body 20,
20', 20'' and can apply an axial force. When this happens, the
piezoelectric driving element would exert an axial force on the
roller body 20 and push said roller body into a more or less
barrel-shaped configuration. As a result of this, a smaller
diameter or a correspondingly larger diameter of the roller body 20
is attained. The actuation with the piezoelectric element or with
the pressurized flow agent is also suitable for dynamic adjustment
processes during the operation of the printing machine.
[0053] A further option is to first achieve a basic calibration of
the outside diameter of at least one of the transport rollers with
the use of the mechanical actuating arrangement 19, for example by
way of a screw adjustment as shown in FIGS. 3, 4 and 5.
Subsequently, a dynamic adjustment of the outside diameter during
operation of the printing machine 1 is used, for example in order
to equalize fluctuations of the input rate of revolutions. The
dynamic adjustment is achieved with the use of a piezo element to
exert an axial force, said piezo element is provided on the
transport rollers 12, 12' of FIGS. 3 and 4 instead of a disk 24,
24' or in addition to these disks. Furthermore, a dynamic
adjustment is achieved by way of pressurized flow agents (FIG.
6).
[0054] The invention has been described with reference to preferred
exemplary embodiments, whereby the individual features of the
described exemplary embodiments are freely combined or interchanged
with each other or both, provided they are compatible. Likewise,
the individual features of the described exemplary embodiments are
omitted. Numerous modifications and designs will be possible for
and obvious to the person skilled in the art, without departing
from the invention as a result of this.
* * * * *